There are many instances in which it is difficult to gain leverage to apply torque to bolts and/or nuts, usually, because of the proximity of other structures. In addition to tight confines of some machinery, there may be the problem of rust and corrosion adhering the components to each other. In these circumstances, impact tools are used to apply a large amount of force with little leverage. Impact tools range from a simple hammer to air hammers, hydraulic rams and electric ultrasonic drivers.
Concomitantly, it may be impossible to directly apply the force of the impact tools perpendicularly to the axis of rotation of the bolts or nuts. In such situations, a link is required between the impact tool and the bolt to vector the force. Conventionally, the link is used to vector the force only in the plane of rotation.
U.S. Pat. No. 1,923,122 to Smith discloses an impact wrench driven by an air hammer. A conventional open end wrench has a spherical socket mounted on one end. A link having a spherical end and integral arms is rotatably mounted in the socket. The arms are connected with a pin in the shank of the wrench. The other end of the link is to be fitted onto the air hammer. The link can rotate approximately 180 degrees about the pin in a plane perpendicular to the longitudinal axis of the bolt or nut being loosened or tightened.
McCarthy, U.S. Pat. No. 1,850,239, discloses a manual impact wrench having an open end with a shank connected by a pin such that the shank can rotate approximately 180 degrees in a plane perpendicular with the longitudinal axis of the bolt. The end of the shank is formed with a flat surface which may be struck with a hammer.
Blackmore, U.S. Pat. No. 4,807,349, discloses an apparatus and method for breaking frozen or other tight connections between screw threads by using a rivet gun for impulses along the longitudinal axis of the bolt while applying manual rotational force to the threads.
U.S. Pat. No. 5,161,440 to Jordan discloses a box end wrench having a shank with a pivoting arm mounted on one end to pivot in a plane perpendicular to the longitudinal axis of the bolt. The arm may be attached to a ultrasonic or other vibrational energy source to turn the bolt.
What is needed in the art is an impact wrench which can pivot in the plane of rotation of a bolt and can rotate about the longitudinal axis of the wrench.